New tubes in Rogue M-180 Monoblocks

The KT90 was thin/lean sounding compared to the KT120 in my Apollo monoblocks. Had a KT90 blow up after 1 year of light use -- a nasty short; sparks and a smoked resistor. No such issue with KT120 in the same time period -- that said, it's naive to trust the reliability of any Russian power tube. I've only run both at 40ma. Suppose it might be smart to try 35.

There are some good points to the KT90 sound, and some listeners will prefer them, but I significantly prefer the KT120 9.5 days out of 10. The bass response is more powerful -- and it's not subtle. The KT120 is smoother and less harsh. If this sounds good to you, give it a try. If your system is a bit bass-heavy and/or needs extra sparkle up top, then stay away. Suits my current system. I believe all current Rogue amps -- other than the non-Magnum Atlas/Cronus -- can provide the extra heater draw. My dealer's M180s shipped from Rogue with KT120 installed. They've also got a Cronus Magnum with KT120. EVERY time I've asked Rogue "what about using alternate tube type X that draws Y more heater current" -- amp or preamp -- they've responded "yes, it can handle that". Heck, I run 12BH7 in place of 12AU7 in my Apollos, on top of the KT120.

Does someone try running KT-150 tube on Rogue M-180 amp ?

Rogue has said this is not recommended. I tried an octet of KT150 in my VAC 200iQ's and they were just awful. That amp was designed for KT88 too. I think KT150 is best suited to amps designed around it. 

Just last weekend I finally tried Gold Lion KT88 in my Rogue Apollo Dark. And surprisingly, it's way better than Tung-Sol KT120 (this was a fresh set too). It fixes the dry midrange without affecting dynamics. It's way, way more effective than triode mode if you find your Rogue amp sounding a bit too "solid state" for your tastes (especially in midrange). And the bass of the big Rogue amps is absolutely amazing - nothing else like it.

Sad times to discover this now, when the Gold Lions are hard to get :(

I wish Rogue had been shipping these with Gold Lions all along. The original design, when it was Zeus, was also designed around KT88. I recall Rogue went through some issues with the Electro Harmonix KT88 in the 2000s (some bad batches there) so they were all to happy to switch to the more reliable KT120 when it came out. But the KT88 issues seem to have resolved since then.

What about the input tube ((12AX7)) on the M180’s? I’ve heard it can have a pretty significant impact on sound. Any recommendations on that one?

@500homeruns It does. That’s a fun slot to roll because it’s so easy (one per side, no re-bias). I used MANY on Apollos over the years. Best sounding tube was Mazda (also branded Cifte, Belvu) silver plates 12AX7 if you can handle a little extra energy on top. When I had daker sounding speakers these were divine. DON’T get the Cifte 5751 silver plates, these are brightness cannons.

For a bit of a warmer sound I really liked the GE 5751 TM BP "silver clips" version from ~1953. The later 50s non-"silver clips" TM BP are good too but not quite as magical.

Teles are relatively plentiful (used) and sound really good, just a tier below Mazdas. The ribbed plates are similar to Mazdas. Smooth plates are a little warmer. Most RCAs tend to be a little warm, but not like Mullards. Once in a while a run into an (oddball) obscenely bright RCA which surprises me (in the trash they go).

Various RCAs and Mullards are pretty good, I just preferred the above. Mullards are very warm and "thick" sounding if you need that.

You can even throw in a 12AY7 for something different. I had a red label GE that sounded pretty good (1963 / 64 vintage on red labels).

But you know what, I actually think the Russian re-issues sound really good and offer different tonal balances across the sub-brands. Mullards are warm (like real ones), Tung-Sol a little energetic up top, Gold Lions in between with a nice touch of sweetness.

The good news is most tubes will sound really good and give you a (slightly) different perspective. It really boils down to personal preference and system balance. I had a few dogs (usually just too bright and lean), but they were by far the minority.